DOI: 10.3390/photonics13080739 ISSN: 2304-6732

Quantized Synchronization Mechanism for Negative Transmission Delay of Photons Through a Resonant Atomic Cloud Chamber

Jau Tang

Recent weak-measurement experiments performed by the University of Toronto reported an apparent negative transmission delay associated with photons propagating through a cold rubidium atomic cloud, raising fundamental questions concerning the physical interpretation of negative interaction time. In this work, we develop a second-quantized synchronization framework to describe resonant photon transmission through a collective atomic ensemble. Both the incident photon and the collective atomic excitation are treated as coupled quantum resonators interacting through an effective synchronization Hamiltonian with finite lifetime broadening. An analytical expression for the transmission amplitude and its phase response is derived, demonstrating that the apparent transmission delay naturally becomes negative on the resonance wings owing to coherent interference between direct transmission and resonant absorption–reemission pathways. In contrast, the microscopic excitation time, defined by the time integral of the atomic excitation-number operator, is rigorously proven to remain nonnegative. Numerical simulations using representative parameters for the Toronto cold-rubidium experiment reproduce the experimentally observed order of magnitude of the negative weak delay without introducing empirical fitting parameters. The calculations further show how the apparent delay depends systematically on frequency detuning and the effective collective coupling strength, providing experimentally testable predictions beyond the existing weak-value interpretation. The present synchronization framework therefore resolves the apparent paradox of negative transmission time by demonstrating that the observed temporal advance originates from phase synchronization and quantum interference rather than from a negative microscopic interaction time.

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